Defining a role for non-canonical mTORC1 activity at focal adhesions

雷帕霉素是一种药物，最初是从复活节岛上收集的细菌中分离出来的，也被称为拉帕努伊。它特异性地抑制雷帕霉素复合体1的机械性靶点(MTORC1)，这是一种进化上保守的蛋白质复合体，它整合了有丝分裂和应激信号来控制细胞的生长和代谢。自40年前发现以来，雷帕霉素因其免疫抑制和抗肿瘤特性而被广泛使用。然而，最近，它作为一种有前途的抗衰老药物获得了关注。在酵母、苍蝇、鱼和老鼠等实验室动物模型中的研究表明，雷帕霉素的治疗效果与热量限制相似，后者是促进健康和寿命的最有力的干预措施之一。然而，雷帕霉素在人类中的治疗与一些鲜为人知的副作用有关，包括损害伤口愈合。这些副作用限制了使用雷帕霉素支持健康人类衰老的可行性。在这项研究中，我们想要探索我们已经确定的特定的mTORC1池的作用和调控。我们最近的手稿首次描述了mTORC1可以在细胞边缘被激活，靠近与局灶性粘连相关的蛋白质(Rabanal-Ruiz等人，2021)。这些是专门负责将细胞锚定到细胞外环境的结构。这些结构的动态性质在细胞迁移过程中很重要，细胞迁移是伤口愈合的最早阶段之一，将伤口与外部环境隔绝。我们的初步和已发表的数据表明，mTORC1活性和局灶性粘连存在紧密的相互调节；即局灶性粘连的破坏会损害mTORC1的激活，而相反，抑制mTORC1会导致局灶性粘连的数量、大小和定位的变化。此外，我们的工作表明，这一特定的mTORC1池不是通过经典调节器控制的，因此我们想要准确地确定它是如何控制的。鉴于雷帕霉素对伤口愈合的不利影响，我们认为局灶性粘连附近的mTORC1池在这一过程中发挥着重要而特殊的作用。因此，这项资助的目的是确定局部粘连中控制mTORC1的机制，并确定其在细胞迁移和伤口愈合中的生理作用。这些数据可能会为未来治疗方案的发展提供信息，以减轻雷帕霉素的副作用，使其成为一种健康的衰老干预措施。

Rapamycin is a drug that was originally isolated from bacteria collected on Easter Island, also known as Rapa Nui. It specifically inhibits the mechanistic Target Of Rapamycin Complex 1 (mTORC1), an evolutionarily conserved protein complex that integrates mitogenic and stress signals to control cell growth and metabolism. Since its discovery forty years ago, rapamycin has been used extensively for its immunosuppressive and antitumour properties. More recently however, it has gained attention as a promising anti-ageing drug. Work in laboratory 'animal' models, such as yeast, flies, fish and mice has shown that treatment with rapamycin has similar effects to caloric restriction which is one of the most robust interventions to promote healthspan and lifespan. Rapamycin treatment in humans is however associated with a number of poorly understood side effects, including impaired wound healing. Such side-effects limit the feasibility of using rapamycin to support healthy human ageing. In this study, we want to explore the role and regulation of a specific pool of mTORC1 that we have identified. Our recent manuscript described, for the first time, that mTORC1 can be activated at the cell edge, in close proximity to proteins associated with focal adhesions (Rabanal-Ruiz et al, 2021). These are specialist structures responsible for anchoring cells to the extracellular environment. The dynamic nature of these structures is important during cell migration, one of the earliest stages of wound healing to close the wound off to the outside environment. Our preliminary and published data indicates that there is tight reciprocal regulation of mTORC1 activity and focal adhesions; namely, disruption of focal adhesions impairs mTORC1 activation while conversely, inhibition of mTORC1 leads to changes in focal adhesion number, size and localisation. Furthermore, our work indicates that this specific pool of mTORC1 is not controlled via classical regulators, and thus we want to identify exactly how it is controlled. Given the detrimental impact of rapamycin on wound healing, we propose that the pool of mTORC1 in the vicinity of focal adhesions plays an important and specific role in this process. The aim of this grant is to therefore identify the mechanisms controlling mTORC1 at focal adhesions and determine its physiological role in cell migration and wound healing. These data may inform on the future development of therapeutic options to mitigate the side-effects of rapamycin, allowing its widespread use a healthy ageing intervention.